Disclosed is a processing device of a photo-sensitive material which comprises a conveying device for conveying a photo-sensitive material, a slot die for applying a processing liquid to the photo-sensitive material conveyed by the conveying device, a reservoir tank of the processing liquid, a supply device of the processing liquid for supplying a processing liquid in the reservoir tank of the processing liquid to the slot die, a support roll of the photo-sensitive material arranged at a position opposite to and spaced from a tip of the slot die, a device for detecting a photo-sensitive material, and a driving device for rotating the support roll of the photo-sensitive material which can rotate the support roll at least in the direction reverse to a conveying direction of the photo-sensitive material.